1100 9TH AVE
Office · Seattle · 98101
At a glance
1100 9TH AVE in Seattle, WA is listed on the Seattle / King County property roll as “Office”, parcel (major-minor) 1979200225. The roll records 126,958 sq ft of building area, 8 floors, a 1975 build year and an assessed value of $30,912,000. It last sold for $155,000 in Feb 2026 on a deed covering 3 parcels. 8 active business locations at this address appear in public records.
The building's own benchmarking filing
Energy performance
From the building's own filing under its city's benchmarking ordinance. An ENERGY STAR score of 75 or above means the building outperforms three quarters of comparable buildings nationally. It is a self-reported figure, verified by the city only to the extent the ordinance requires.
Recorded transfers — county roll + state sale file
Sale history
The most recent transfer covered 3 parcels. The price shown is the whole transaction, not this parcel alone, so any per-square-foot figure is measured across everything the deed conveyed. The county record carries no multi-parcel flag for it; the parcels were identified by their identical price, date and ZIP.
| Recorded | Price | Qualification | Source | Instrument |
|---|---|---|---|---|
| Feb 2026 | $155,000 | not rated | County roll | — |
Prices are the consideration recorded in Seattle / King County's public property records. Where a qualification code exists it is the assessor's judgement of whether a transfer was arm's length; transfers without one appear unrated rather than assumed clean. Whether a building is on the market today, and at what price, is not a public record and is not shown here — asking prices, listings and lease terms live in private commercial databases.
Public record — 8 matched business locations
Tenants & business locations
| Company | Suite / floor | Since | Source | Match |
|---|---|---|---|---|
| HARBORSIDE MARKET | — | Mar 2024 | Seattle business licence | address · medium |
| PERFORMANCE HOME MEDICAL | # H1029A | Jan 2024 | Seattle business licence | address · medium |
| NETWORXHEALTH LLC | # M6 AC | Apr 2018 | Seattle business licence | address · medium |
| PUGET SOUND HIGH VALUE NETWORK LLC | — | Jan 2015 | Seattle business licence | address · medium |
| VIRGINIA MASON INSTITUTE | — | Jan 2009 | Seattle business licence | address · medium |
| ABM INDUSTRY GROUPS LLC | — | Jun 2007 | Seattle business licence | address · medium |
| SOURCECORP BPS INC | — | Mar 2005 | Seattle business licence | address · medium |
| BUCK PAVILLION | — | Jul 1994 | Seattle business licence | address · medium |
Seattle / King County assessment roll
Parcel record
| Field | Value |
|---|---|
| parcel (major-minor) | 1979200225 |
| Site address | 1100 9TH AVE |
| Land use (DOR) | — Office |
| Building area (actual) | 126,958 sq ft |
| Floors / units / buildings | 8 / — / 1 |
| Lot size | — |
| Year built | 1975 |
| Zoning (primary) | — |
| Land value | $8,832,000 |
| Building value | — |
| Total assessed value | $30,912,000 |
Recorded owner (assessment roll)
No owning organisation shown. Where the county roll names a private individual, the name and mailing address are not published here.
Location
- Address
- 1100 9TH AVE
- City
- Seattle
- ZIP
- 98101
Within ~650 m
Nearby office buildings
No other office parcels within ~650 m.
How does 1100 9TH AVE compare with other Seattle office buildings?
At 126,958 sq ft, 1100 9TH AVE is about 3 times the size of the average office building on the Seattle / King County roll, which comes to 46,649 sq ft across 4,289 buildings.
Its assessed value works out to $243 per square foot of building area, against $230 across all office floor area on the roll.
The last recorded sale priced it at $0 per square foot across the parcels conveyed.
Does the owner of 1100 9TH AVE hold other Seattle office property?
Seattle / King County's published roll does not include owner names, so no owner is shown for any parcel in this metro.
What has happened at 1100 9TH AVE recently?
1 recorded transfer is on file for this parcel, the latest dated Feb 2026.
The building files energy-benchmarking disclosures — 1 report year are matched to this parcel.
What does “Office” mean for this parcel?
The Seattle / King County roll classifies parcel (major-minor) 1979200225 as “Office”. BuildingCensus includes a parcel in its office census when the roll gives it an office-class use, so the label is the county's, not an inference.
Frequently asked questions
Who owns 1100 9TH AVE?
Seattle / King County's published roll does not include owner names, so no owner is shown.
What companies have offices at 1100 9TH AVE?
8 active business locations at this building appear in Seattle / King County public records, including HARBORSIDE MARKET, PERFORMANCE HOME MEDICAL, NETWORXHEALTH LLC, PUGET SOUND HIGH VALUE NETWORK LLC, VIRGINIA MASON INSTITUTE. Public records under-count tenants that don't hold a local receipt or register the address.
How big is 1100 9TH AVE?
The Seattle / King County roll records 126,958 sq ft of building area, 8 floors, a build year of 1975.
What is the assessed value of 1100 9TH AVE?
$30,912,000 on the Seattle / King County roll. Assessed values are taxable-roll figures, not market prices.
When did 1100 9TH AVE last sell?
The last recorded transfer was in Feb 2026 for $155,000, on one deed conveying 3 parcels ($0 per square foot).
What is the parcel (major-minor) for 1100 9TH AVE?
Parcel (major-minor) 1979200225, site address 1100 9TH AVE, Seattle. It is the key to look the parcel up in the King County Assessor bulk extracts and Seattle open data (Seattle / King County).
More around 1100 9TH AVE
- Seattle / King County office buildings· 4,289 buildings
- Owner's other properties· 2 properties
- HARBORSIDE MARKET· tenant on record
- PERFORMANCE HOME MEDICAL· suite # H1029A
- NETWORXHEALTH LLC· suite # M6 AC
- PUGET SOUND HIGH VALUE NETWORK LLC· tenant on record
- Federal office leases in WA
- Office census — all metros
Everything here comes from public records, and public records go stale. If you know better, say so.
Data provenance — public records only
- Seattle / King County — King County Assessor bulk extracts and Seattle open data. Washington law restricts commercial use of lists of individuals, so this metro is built without personal names by design: the county's name-stripped account file provides mailing addresses (portfolios group by mailing cluster, unnamed), sales show price and date but never buyer or seller, and tenants are business licence trade names.
Every fact on this page is drawn from the government records above — no listing sites, no scraped platforms, no third-party images. Facts from public records are uncopyrightable; each tenancy row carries its source and match confidence. Records can lag reality — a business-tax receipt or registration at an address is evidence of occupancy, not a lease confirmation.
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Dataset updated . Source: Seattle / King County assessment roll, parcel (major-minor) 1979200225.
About this data
Source: King County Assessor bulk extracts and Seattle open data (Seattle / King County), as published September 20, 2026. See the methodology for how records are matched, cleaned and scored.
Cite as: BuildingCensus, “1100 9TH AVE, Seattle, WA (parcel (major-minor) 1979200225)”, https://buildingcensus.com/offices/seattle/office-building-b4ad8bb0 (data as of September 20, 2026).